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      • KCI등재

        A Frequency-Tracking Method Based on a SOGI-PLL for Wireless Power Transfer Systems to Assure Operation in the Resonant State

        Ping-an Tan,Haibing He,Xieping Gao 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

        Wireless power transfer (WPT) technology is now recognized as an efficient means of transferring power without physical contact. However, frequency detuning will greatly reduce the transmission power and efficiency of a WPT system. To overcome the difficulties associated with the traditional frequency-tracking methods, this paper proposes a Direct Phase Control (DPC) approach, based on the Second-Order Generalized Integrator Phase-Locked Loop (SOGI-PLL), to provide accurate frequency-tracking for WPT systems. The DPC determines the phase difference between the output voltage and current of the inverter in WPT systems, and the SOGI-PLL provides the phase of the resonant current for dynamically adjusting the output voltage frequency of the inverter. Further, the stability of this control method is analyzed using the linear system theory. The performance of the proposed frequency-tracking method is investigated under various operating conditions. Simulation and experimental results convincingly demonstrate that the proposed technique will track the quasi-resonant frequency automatically, and that the ZVS operation can be achieved.

      • SCIESCOPUSKCI등재

        A Frequency-Tracking Method Based on a SOGI-PLL for Wireless Power Transfer Systems to Assure Operation in the Resonant State

        Tan, Ping-an,He, Haibing,Gao, Xieping The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

        Wireless power transfer (WPT) technology is now recognized as an efficient means of transferring power without physical contact. However, frequency detuning will greatly reduce the transmission power and efficiency of a WPT system. To overcome the difficulties associated with the traditional frequency-tracking methods, this paper proposes a Direct Phase Control (DPC) approach, based on the Second-Order Generalized Integrator Phase-Locked Loop (SOGI-PLL), to provide accurate frequency-tracking for WPT systems. The DPC determines the phase difference between the output voltage and current of the inverter in WPT systems, and the SOGI-PLL provides the phase of the resonant current for dynamically adjusting the output voltage frequency of the inverter. Further, the stability of this control method is analyzed using the linear system theory. The performance of the proposed frequency-tracking method is investigated under various operating conditions. Simulation and experimental results convincingly demonstrate that the proposed technique will track the quasi-resonant frequency automatically, and that the ZVS operation can be achieved.

      • SCIESCOPUSKCI등재

        The effects of physical decontamination methods on zirconia implant surfaces: a systematic review

        Tan, Nathan Chiang Ping,Khan, Ahsen,Antunes, Elsa,Miller, Catherine M,Sharma, Dileep Korean Academy of Periodontology 2021 Journal of Periodontal & Implant Science Vol.51 No.-

        Purpose: Peri-implantitis therapy and implant maintenance are fundamental practices to enhance the longevity of zirconia implants. However, the use of physical decontamination methods, including hand instruments, polishing devices, ultrasonic scalers, and laser systems, might damage the implant surfaces. The aim of this systematic review was to evaluate the effects of physical decontamination methods on zirconia implant surfaces. Methods: A systematic search was conducted using 5 electronic databases: Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane. Hand searching of the OpenGrey database, reference lists, and 6 selected dental journals was also performed to identify relevant studies satisfying the eligibility criteria. Results: Overall, 1049 unique studies were identified, of which 11 studies were deemed suitable for final review. Air-abrasive devices with glycine powder, prophylaxis cups, and ultrasonic scalers with non-metal tips were found to cause minimal to no damage to implantgrade zirconia surfaces. However, hand instruments and ultrasonic scalers with metal tips have the potential to cause major damage to zirconia surfaces. In terms of laser systems, diode lasers appear to be the most promising, as no surface alterations were reported following their use. Conclusion: Air-abrasive devices and prophylaxis cups are safe for zirconia implant decontamination due to preservation of the implant surface integrity. In contrast, hand instruments and ultrasonic scalers with metal tips should be used with caution. Recommendations for the use of laser systems could not be fully established due to significant heterogeneity among included studies, but diode lasers may be the best-suited system. Further research-specifically, randomised controlled trials-would further confirm the effects of physical decontamination methods in a clinical setting.

      • KCI등재

        The effects of physical decontamination methods on zirconia implant surfaces: a systematic review

        Nathan Chiang Ping Tan,Ahsen Khan,Elsa Antunes,Catherine M Miller,Dileep Sharma 대한치주과학회 2021 Journal of Periodontal & Implant Science Vol.51 No.5

        Purpose: Peri-implantitis therapy and implant maintenance are fundamental practices to enhance the longevity of zirconia implants. However, the use of physical decontamination methods, including hand instruments, polishing devices, ultrasonic scalers, and laser systems, might damage the implant surfaces. The aim of this systematic review was to evaluate the effects of physical decontamination methods on zirconia implant surfaces. Methods: A systematic search was conducted using 5 electronic databases: Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane. Hand searching of the OpenGrey database, reference lists, and 6 selected dental journals was also performed to identify relevant studies satisfying the eligibility criteria. Results: Overall, 1049 unique studies were identified, of which 11 studies were deemed suitable for final review. Air-abrasive devices with glycine powder, prophylaxis cups, and ultrasonic scalers with non-metal tips were found to cause minimal to no damage to implant-grade zirconia surfaces. However, hand instruments and ultrasonic scalers with metal tips have the potential to cause major damage to zirconia surfaces. In terms of laser systems, diode lasers appear to be the most promising, as no surface alterations were reported following their use. Conclusion: Air-abrasive devices and prophylaxis cups are safe for zirconia implant decontamination due to preservation of the implant surface integrity. In contrast, hand instruments and ultrasonic scalers with metal tips should be used with caution. Recommendations for the use of laser systems could not be fully established due to significant heterogeneity among included studies, but diode lasers may be the best-suited system. Further research—specifically, randomised controlled trials—would further confirm the effects of physical decontamination methods in a clinical setting.

      • KCI등재

        Pimecrolimus increases the melanogenesis and migration of melanocytes in vitro

        Ping Xu,Jie Chen,Cheng Tan,Ren-Sheng Lai,Zhong-Sheng Min 대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

        Vitiligo is an intriguing depigmentary disorder and is notoriously difficult to be treated. The ultimate goal of vitiligo treatment is to replenish the lost melanocytes by immigration from hair follicle and to restore the normal function of melanogenesis by residual melanocytes. There are two types of topical calcineurin inhibitors called tacrolimus and pimecrolimus, and are recommended as the first-line treatments in vitiligo. Although pimecrolimus is efficacious for the repigmentation of vitiligo, its intrinsic mechanisms have never been investigated in vitro. This research aimed to study the ability of pimecrolimus on stimulating melanogenesis, melanocyte migration and MITF (microphthalmia associated transcription factor) protein expression. Results showed that pimecrolimus at the dosages of 1, 10, 102 nM were neither mitogenic nor cytotoxic to melanocytes. The addition of pimecrolimus at 10, 102 and 103 nM significantly increased intracellular tyrosinase activity, which was consistent with the elevated content of melanin content at the same concentrations. The peak effect was seen at 72 h in response to 102 nM pimecrolimus. Results of the wound scratch assay and Transwell assays indicate that pimecrolimus is effective in facilitating melanocyte migration on a collagen IV-coated surface. In addition, MITF protein yield reached the highest by pimecrolimus at 102 nM. In brief, pimecrolimus enhances melanin synthesis as well as promotes migration of melanocytes directly, possibly via their effects on MITF protein expression.

      • SCISCIESCOPUS

        The MALATANG Survey: The <i>L</i><sub>GAS</sub>-<i>L</i><sub>IR</sub> Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN <i>J</i> = 4 → 3 and HCO<sup>+</sup><i>J</i> = 4 → 3

        Tan, Qing-Hua,Gao, Yu,Zhang, Zhi-Yu,Greve, Thomas R.,Jiang, Xue-Jian,Wilson, Christine D.,Yang, Chen-Tao,Bemis, Ashley,Chung, Aeree,Matsushita, Satoki,Shi, Yong,Ao, Yi-Ping,Brinks, Elias,Currie, Malco American Astronomical Society 2018 The Astrophysical journal Vol.860 No.2

        <P>We present HCN J = 4 -> 3 and HCO+ J = 4 -> 3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2' x 2' region at 14 '' (FWHM) resolution (corresponding to linear scales of similar to 0.2-1.0 kpc). The L-IR-L'(dense) relation, where the dense gas is traced by the HCN J = 4 -> 3 and the HCO+ J = 4 -> 3 emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, L-IR/L'(dense), shows systematic variations with L-IR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between L-IR/L'(dense) ratio and the warm-dust temperature gauged by the 70 mu m/100 mu m flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFEdense), appear to be nearly independent of the dense gas fraction (f(dense)) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f(dense) when combining our data with those on local (ultra) luminous infrared galaxies and high-z quasars. The mean L'(HCN(4-3))/L'(HCO+(4-3)) line ratio measured for the six targeted galaxies is 0.9 +/- 0.6. No significant correlation is found for the L'(HCN(4-3)) L'(HCO+(4-3)) ratio with the star formation rate as traced by L-IR, nor with the warm-dust temperature, for the different populations of galaxies.</P>

      • SCOPUSKCI등재

        Theoretical Study on the Reaction Mechanism of Azacyclopropenylidene with Epoxypropane: An Insertion Process

        Tan, Xiaojun,Wang, Weihua,Li, Ping Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

        The reaction mechanism between azacyclopropenylidene and epoxypropane has been systematically investigated employing the second-order M${\o}$ller-Plesset perturbation theory (MP2) method to better understand the reactivity of azacyclopropenylidene with four-membered ring compound epoxypropane. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. It was found that for the first step of this reaction, azacyclopropenylidene can insert into epoxypropane at its C-O or C-C bond to form spiro intermediate IM. It is easier for the azacyclopropenylidene to insert into the C-O bond than the C-C bond. Through the ring-opened step at the C-C bond of azacyclopropenylidene fragment, IM can transfer to product P1, which is named as pathway (1). On the other hand, through the H-transferred step and subsequent ring-opened step at the C-N bond of azacyclopropenylidene fragment, IM can convert to product P2, which is named as pathway (2). From the thermodynamics viewpoint, the P2 characterized by an allene is the dominating product. From the kinetic viewpoint, the pathway (1) of formation to P1 is primary.

      • KCI등재

        Kinetics and mechanism study of H-acid degradation by peroxymonosulfate activation with Co3O4-Fe2O3/Al2O3

        Ping Dai,Xiaowei Sun,Dongyan Xu,Feng Tan 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.6

        Alumina supported bimetallic cobalt-iron oxide (Co3O4-Fe2O3/Al2O3) catalyst was prepared via co-impregnation of boehmite with the mixture solution of cobalt nitrate and iron nitrate followed by calcination in air. X-ray photoelectron spectroscopy and high-resolution transmission electron microscope analyses confirmed the existence of highly dispersed Co3O4 and Fe2O3 nanoparticles in the as-prepared catalysts. The catalytic activity of Co3O4-Fe2O3/Al2O3 was evaluated for the degradation of H-acid in aqueous solution by heterogeneous activation of peroxymonosulfate. The results indicated that the Co3O4-Fe2O3/Al2O3 catalyst exhibited an identical initial activity but much better recyclability than Co3O4/Al2O3 due to its low amount of metal leaching and possible redox circle of Co(II)/Co(III). Electron paramagnetic resonance spectroscopy and radical quenching experiments suggested that singlet oxygen (1O2) contributed much more than ·OH and SO4 • to H-acid degradation, and the degradation mainly followed a nonradical reaction mechanism.

      • Discovery of Endothelium and Mesenchymal Properties of Primo Vessels in the Mesentery

        Ping, An,Zhendong, Su,Jingxing, Dai,Yaling, Liu,Bae, Kyung-Hee,Shiyun, Tan,Hesheng, Luo,Soh, Kwang-Sup,Ryu, Yeon Hee,Kim, Sungchul Hindawi Publishing Corporation 2013 Evidence-based Complementary and Alternative Medic Vol.2013 No.-

        <P>Recent evidences demonstrated that endothelial-to-mesenchymal transition (EndMT) has a crucial role in cancer and is recognized as a unique source of cancer-associated fibroblasts (CAFs). Primo vascular system (PVS) is a new circulatory system which may play an important role in cancer metastasis and regeneration. In the current study, we applied previously established time-saving method to identify primo vessels and further investigated the immunocytochemical properties of primo vessels. Both primo vessels and primary primo vessel cells in the mesentery expressed endothelial markers and fibroblast markers. Double-labeling experiments demonstrated that endothelial and fibroblast markers are coexpressed in primo vessels. In addition, under the stimulation of TGF-<I>β</I>1 <I>in vitro,</I> primary primo vessel cells differentiated into fibroblasts. Therefore, we found that primo vessels in the mesentery had a transitional structure between endothelium and mesenchymal. This is a new finding of EndMT in normal postnatal animals.</P>

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